Read the first few episodes will read later when I have more time.
1) child abuse isn't so bad. I've depicted far worse child abuse and domestic violence in my previous comics. As long as you steer clear of nudity and extreme violence (in the visual depiction sense) it seems to be fine.
2) the drop off part? Happens to everyone. You see, people often read the first few episodes and then they make up their mind if they like it or not. Or totally forget due to time constraints.
3) art wise? Not being mean here but definitely needs work. An obvious thing I noticed is size consistency between characters. How tall exactly are they compared to one another?
4) not "offensive" as far as I'm concerned. But again, purely my opinion and I work with pretty dark themes in my comics and I'm also very pro free speech (nearly got arrested for it on a few occasions during my youth) so it probably takes far more to offend me than the average person.